The technology of electroplating is well known. Electroplating or electro deposition involves the immersion of a cathode and anode in an electrolyte. With the application of a current to the anode, metal salts within the electrolyte are reduced at the electrolyte—cathode interface and plate out onto the cathode.
Electroplating is most commonly used to change the surface properties of a work piece. Physical properties such as strength, wear and abrasion resistance, resistance to ambient conditions such as temperature extremes and impact can all be affected by the deposition of adjunct metal coatings to the work piece. Other properties such as lubricity and corrosion resistance, may also be affected by electroplating. Electroplating is also commonly used to affect the aesthetic properties of a work piece through the application of a more preferred surface coating onto the object.
The literature is replete with electroplating processes and devices which have been used previously. Examples of devices and processes include those disclosed by Oliver in U.S. Pat. No. 1,533,805 as an electroplating rack which addresses the routine problem of hangers being coated and needing cleaning. Oliver discloses hangers which may be removed and replaced during cleaning so as to avoid down time in the plating process. Davis U.S. Pat. No. 2,484,079 discloses a hydraulically operated plating machine intended to avoid many of the concerns which arose with chain driven plating apparatus. Similar to Oliver, Belke, U.S. Pat. No. 2,820,757, discloses a plating rack assembly. The Belke plating rack is intent on maintaining low electrical resistance connections between the rack and the articles to be electroplated through assembly, plating, and disassembly. Henson, U.S. Pat. No. 2,898,285 also addresses the concern of errant metal deposits on the electroplating rack by the use conductive elements placed on the rack.
Novitsky, U.S. Pat. No. 3,314,877 discloses a plating and anodizing rack having a cylindrical shape. Chenevier, U.S. Pat. No. 3,607,707 also addresses the corrosivity of the plating process and the effect on the racks used therein. Fueki et al., U.S. Pat. No. 3,939,056 discloses an electroplating rack which is intended to reduce the amount of plating build up on the rack. The evident problem is that the buildup of deposits on the plating rack is a waste of material, and inevitably takes the rack out of service to be cleaned. Without cleaning, plating will further erode the structural integrity of the rack over time.
Of the problems addressed in the technical field of electroplating, one concern is the consistent and thorough cleaning of the work piece prior to the plating process as well as consistent and thorough electro deposition during the plating process.
Work pieces come in many sizes, shapes and with many different points of detail, patterning and design. Depending on the purpose of the deposition, the plating coverage of the work piece can be critical. Further coverage of the work piece is not always easy or intuitive.
Work pieces with a high level of detail can offer concerns over the permeation of the plating bath into the points of detail. Work pieces having walls that extend outwardly from a closed bottom (for example having the shape of a cup), are also one further design that may present problems with cleaning and plating.
Conventional plating processes such as those disclosed above, place the work piece in the plating bath through an up and down motion. While extended time in the bath can overcome certain concerns of the bath permeating the definition of the work piece, practical limitations abound.
Examples of recent attempts at plating racks and assemblies include Patent Application Publication US 2002/0179438 which discloses a plating clamp assembly intended to selectively clamp a work piece and thus allow for selective coating of the work piece.
U.S. Pat. No. 7,850,830 discloses a plating rack having a cylindrical central portion which moves through mechanical action to, in turn, move work pieces through the plating bath.
Patent Application Publication US 2014/0076720 discloses an electro polishing fixture with a lever arm intended to maintain electrical connection and reposition.
Seemingly self-evident, cleaning and then plating is easier to discuss than do. The submersion of a fixed piece in a stationary position on conventional racks does not always allow for penetration of cleaning solution into cracks and crevices of the work piece. Varying patterns as well as shapes and designs present concerns that often leave individual work pieces either partially cleaned or partially plated, making the work piece less than acceptable for application into the intended environment of use.
Despite these advances, further work needs to be done to reposition or reorient work pieces in the plating bath to accommodate penetration or permeation of the bath into the definition of the work piece. Thus there is a need to solve these and other problems found in the art.